The effectiveness of light/dark exposure to treat insomnia in female nurses undertaking shift work during the evening/night shift

J Clin Sleep Med. 2013 Jul 15;9(7):641-6. doi: 10.5664/jcsm.2824.


Study objectives: The present study investigated whether bright light exposure during the first half of the evening/night shift combined with light attenuation in the morning is effective in improving sleep problems in nurses undertaking rotating shift work who suffer from clinical insomnia.

Methods: This was a prospective, randomized control study. The Insomnia Severity Index (ISI) and the Hospital Anxiety Depression Scale (HADS) were used to evaluate insomnia and anxiety/depression severity, respectively. Female hospital nurses on rotating shifts during the evening or night shift with an ISI score > 14 were enrolled. Subjects in the treatment group (n = 46) were exposed to bright light at 7,000-10,000 lux for ≥ 30 minutes. Exposure was continued for at least 10 days during 2 weeks, and the subjects avoided daytime outdoor sun exposure after work by wearing dark sunglasses. Subjects in the control group (n = 46) were not exposed to bright light, but also wore sunglasses after work. Statistical analyses were performed to examine group differences and differences across treatments.

Results: After treatment, the treatment group showed significant improvements in the ISI score and the HADS total and subscale scores as compared with pre-treatment. The ISI, HADS, and subscales of the HADS scores were significantly improved across treatments in the treatment group as compared with the control group.

Conclusions: The design of this study is easy to put into practice in the real world. This is the first study to document that a higher intensity and briefer duration of bright light exposure during the first half of the evening/night shift with a daytime darkness procedure performed in rotating shift work female nurses suffering from clinical insomnia could improve their insomnia, anxiety, and depression severity.

Keywords: Bright light; anxiety; circadian rhythm; depression; insomnia; nurses; rotating shift; shift work.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anxiety Disorders / complications
  • Anxiety Disorders / psychology
  • Anxiety Disorders / therapy
  • Darkness*
  • Depressive Disorder / complications
  • Depressive Disorder / psychology
  • Depressive Disorder / therapy
  • Female
  • Humans
  • Phototherapy / methods*
  • Prospective Studies
  • Psychiatric Status Rating Scales / statistics & numerical data
  • Severity of Illness Index
  • Sleep Disorders, Circadian Rhythm / complications
  • Sleep Disorders, Circadian Rhythm / psychology
  • Sleep Disorders, Circadian Rhythm / therapy*
  • Sleep Initiation and Maintenance Disorders / complications
  • Sleep Initiation and Maintenance Disorders / psychology
  • Sleep Initiation and Maintenance Disorders / therapy*
  • Taiwan
  • Work Schedule Tolerance / physiology*
  • Work Schedule Tolerance / psychology